Mapping Summertime Evolution of Ice in the North and South Poles with CRISM

Grant #: NNX13AJ73G
Senior Scientist: Adrian Brown

We propose to use data from the CRISM visible/near infrared (VNIR) mapping spectrometer to examine the spectral changes that take place in the north and south polar caps during summer. It is well known that the residual cap in the north is composed of water ice and in the south is composed of CO2 ice, but changes within the warm season are not yet understood. This proposal will augment recent work on CRISM observations of the springtime evolution and retreat of the seasonal cap of both hemispheres: (Brown et al. 2009 for south and Brown et al 2012 for north). 

We will examine three scientific questions: 

1. Thermal metamorphism has been reported in isolated locations for the north polar cap (Langevin et al, 2005; Brown et al, 2012). Does this process continue all summer, when does it commence and when does it end as a function of time and location across the pole? 

2. Water ice re-deposition onto the summertime cap has been reported (Bass and Paige, 2000). Brown et al., 2012 have shown that this coldtrapping process is asymmetric during mid spring. Is this process uniform around the cap during summertime? What are the effects on ice grain size? 

3. Albedo changes occur on both caps through the VNIR due to dust deposition (Byrne, 2008). We will investigate this process during summertime images by tracking VNIR albedo and looking for evidence that this process is occurring.